check key inside object inside array javascript code example

Example 1: check object in array javascript

var obj = {a: 5};
var array = [obj, "string", 5]; // Must be same object
array.indexOf(obj) !== -1 // True

Example 2: react array if id is present do not add element

addPerson = (person) => {
    let filteredPerson = this.state.likes.filter(like => like.name !== person.name);
    this.setState({
      likes: [...filteredPerson, person]
    })        
  }